The present invention relates generally to the field of electronic devices, and in particular to the thermal management of high-powered electronic devices.
Electronic devices generate heat during operation. Thermal management refers to the ability to keep temperature-sensitive elements in an electronic device within a prescribed operating temperature. Thermal management has continually evolved to address the increased heat generation created within such electronic devices as a result of the increased processing speed/power that is usually associated with each new generation of electronic devices.
Historically, electronic devices were cooled by a natural convection thermal management technique. The cases or packaging of these prior art electronic devices were designed with openings (e.g., slots) strategically located to allow warm air to escape and cooler air to be drawn in.
The advent of high performance electronic devices now requires more innovative thermal management. Each increase in processing speed and power generally carries a “cost” of increased heat generation such that natural convection is no longer sufficient to provide proper thermal management.
Several methods have been employed for cooling high performance electronic devices. One common method of cooling an electronic device includes attaching one or more heat sinks to the electronic device. A heat sink is typically used in combination with a fan that forces air to pass by the heat sink and/or the electronic device.
There are several problems with cooling systems that utilize some form of a heat sink and fan combination. One problem is that more air flow is generally needed in order adequately dissipate heat from the electronic device. This increase in air flow is typically generated by a larger fan and/or increased fan speed which can result in unwanted acoustic noise. Another problem is that the fan must typically be located too closely to the fins of the heat sink to generate fully developed air flow. In addition, when a large fan is used in conjunction with a heat sink to cool an electronic component, a large percentage of the air moved by the system fan does not go through the heat sink. As a result, even large fans are not a sufficient thermal solution for cooling some electronic devices.
An alternative and more costly system to manage the thermal energy output of high-powered electronic devices is a liquid cooling system. Most liquid cooling systems include a heat exchanger that is thermally connected to the electronic device.
A relatively recent trend has seen the use of “two-phase” cooling systems to cool high-powered electronic devices. These two phase cooling systems include an evaporator or flow channels that remove thermal energy from the electronic device. The thermal energy causes a coolant within the evaporator or flow channels to turn from a liquid into a vapor (i.e., to evaporate) or vapor-liquid mixture.
These “two-phase” cooling systems suffer from several drawbacks. One drawback is that the systems require the use of a pump. These pumps require maintenance and commonly break down or leak onto one or more of the electrical components. Another drawback is that many electronic devices are now putting out so much thermal energy that existing two-phase cooling systems often have trouble thermally managing electronic devices under more extreme operating conditions.
Since many electronic systems are not able to effectively cool the high performance electronic devices that are within such systems under certain operating conditions, an electronic system is needed that provides superior cooling to high-powered electronic devices under a variety of operating conditions.